EP2295267A1

EP2295267A1 - Tire stud for snow tire

Info

Publication number: EP2295267A1
Application number: EP09170046A
Authority: EP
Inventors: Wu-Ming Liang
Original assignee: Chang Ping-Nan
Current assignee: Chang Ping-Nan
Priority date: 2009-09-11
Filing date: 2009-09-11
Publication date: 2011-03-16

Abstract

A tire stud having high binding strength, high wear resistance and falling preventive characteristics is disclosed to include a jacket (10) that is embedded in the tire (50) and has a circular base (11) and a shank (12) extended from the circular base (11) and terminating in a tapered bearing portion (13), a wearing ring (30) that has a top face (32), a tapered bottom face (33), a bottom edge (34) located on the center of the lowest part of the tapered bottom face (33) and a tapered through hole (31) cut through the top face (32) and the bottom edge (34) and press-fitted onto the tapered bearing portion (13) of the jacket (10), and a pin (40) axially driven into the tapered bearing portion (13) of the shank (12) of the jacket (10) and partially protruding beyond the tapered bearing portion (13).

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention:

The present invention relates to tire stud for snow tire and more particularly, to a wear-resistant and falling preventive tire stud for snow tire.

2. Description of the Related Art:

Referring to FIG. 1, a conventional tire stud is shown comprising a jacket 1 and a pin 2. The jacket 1 is made of a soft metal, such as soft ferrite, aluminum or their alloys. The pin 2 is inserted into the jacket 1 from the top, having a top part exposed to the outside of the jacket 1.
When the tire stud is inserted into a hole molded into the tread design of a tire 3 and the tire 3 is rotated forwards or backwards, the top (outer) end 101 of the jacket 1 will be forced against the road or ice on the road. After a long use, the jacket 1 is worn at the top (outer) end 101, and a clearance 102 appears in the tread design around the top (outer) end 101 of the jacket 1, affecting the binding strength between the pin 2 and the jacket 1 and weakening the structural strength of the tire stud. Continuous use of the tire 3 will cause a clearance 103 to appear between the pin 2 and the jacket 1. Continuously using the tire 3 may cause the pin 2 to fall from the jacket 1, or may cause the entire tire stud to fall from the tire 3. More particularly, when the front side of the top end of the jacket 1 starts to wear after a long use, the pressure acted upon the pin 2 during a backward movement of the vehicle may force the jacket 1 to deform, resulting in falling of the pin 2 from the jacket 1.
Further, according to the aforesaid conventional design, the pin 2 is directly inserted into the jacket 1 by force. When forcing the pin 2 into the jacket 1, the top opening of the jacket 1 will be forced to expand. When the top opening of the jacket 1 expands, the pin 2 tends to be forced away from the jacket 1 during running of the vehicle. Further, the aforesaid conventional design of tire stud has low torsional strength. This drawback causes the tire stud to be forced away from the tire easily when the steering direction of the tire is being changed.

SUMMARY OF THE INVENTION

The present invention has been accomplished under the circumstances in view. It is one object of the present invention to provide a tire stud for snow tire, which has high binding strength and high wear resistance characteristics and will not fall from the tire.
To achieve this and other objects of the present invention, a tire stud comprises a jacket for embedding in the tread design of a snow tire, at least one wearing ring supported on the bearing portion of said jacket and a pin being axially driven into the shank. The jacket has a circular base and a shank perpendicularly upwardly extended from the center of the circular base. The shank has a bearing portion formed of at least a part thereof. Each wearing ring has a top face disposed at the top side, a tapered bottom face disposed at the bottom side, a bottom edge located on the center of the lowest part of the tapered bottom face and a through hole vertically cut through the center of the top face and the center of the bottom edge and press-fitted onto the tapered bearing portion of the jacket. The pin partially protrudes beyond the shank of the jacket when it is driven into the jacket.
The tire stud further comprises a locating ring press-fitted onto the bearing portion of the shank of the jacket and disposed at a bottom side relative to the at least one wearing ring. The locating ring has a through hole cut through top and bottom sides thereof and press-fitted onto the bearing portion of the shank of the jacket and at least one pawl protruded from the top side thereof for engaging into the inside of the tread design of a snow tire.
Further, the at least one wear ring has a hardness higher than the hardness of the jacket.
Further, the pin has a hardness higher than the hardness of the jacket.
Further, the bottom face of the each wear ring is a tapered face having a diameter gradually reducing in direction from the top face toward the bottom edge of the wear ring.
Further, the distance between the center and each pawl of the locating ring is not shorter than the radius of the at least one wear ring.
Further, the shank of the jacket has a coarsened peripheral surface.
Further, the at least one wear ring is selected from a material group of ferrite, aluminum and their alloys.
Further, the jacket is selected from a material group of ferrite, aluminum, copper and their alloys, and plastics.
Further, the pin is made of a metal alloy containing ferrite.
Further, the bearing portion of the shank of the jacket has a flange formed of a top end thereof and stopped at the top face of one the wear ring after the insertion of the pin into the shank.
Further, the through hole of each wear ring is a tapered through hole having a diameter gradually increasing in direction from the top face toward the bottom edge of the respective wear ring; the bearing portion of the shank of the jacket is tapered bearing portion fitting the tapered through hole of each wear ring.
Further, the metal alloy is selected from a group of tungsten steel, cast iron, alloy steel and stainless steel.
Further, the locating ring is selected from a material group of ferrite, aluminum, copper and their alloys, and plastics.
Further, the through hole of the locating ring is a tapered through hole having a diameter gradually increasing in direction from the top face toward the bottom edge of the respective wear ring; the bearing portion of the shank of the jacket is a tapered bearing portion fitting the tapered through hole of the locating ring.
The tire stud of the present invention has the relatively harder wear ring be attached to the tapered bearing portion of the shank of the jacket to enhance wear resistance so that the tire stud does not wear quickly with use and is more durable when compared to the prior art design. Further, under the protection of the flange of the jacket, the wear ring is prohibited from falling away from the jacket. Thus, the tire stud of the present invention has wear resistance and falling preventive characteristics.
Further, the arrangement of the extra locating ring enhances the strength of the tire stud against torque during rotation of the tire, eliminating or reducing the possibility of falling of the tire stud from the tire.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic sectional view showing a tire stud mounted in the tread design of a tire according to the prior art.
FIG. 2 corresponds to FIG. 1, showing a clearance appeared in the tread design around the top (outer) end of the jacket and the pin vibrated relative to the jacket.
FIG. 3 is an elevational assembly view of a tire stud in accordance with a first embodiment of the present invention.
FIG. 4 is an exploded view of the tire stud in accordance with the first embodiment of the present invention.
FIG. 5 is a schematic sectional view of the first embodiment of the present invention, showing the tire stud installed in the tread design of a tire of a vehicle.
FIG. 6 is an enlarged view of part A of FIG. 5.
FIG. 7 is a schematic drawing showing a tire stud installed in a snow tire in accordance with a second embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 3 and 4, a tire stud for snow tire in accordance with a first embodiment of the present invention is shown comprising a jacket 10, at least one wear ring 30 and a pin 40.
Referring to FIG. 5, the jacket 10 is embedded in the inside 52 (tread design) of the tire 50 and exposed to the outside of the surface 51 of the tire 50. The jacket 10 has a circular base 11, and a shank 12 perpendicularly upwardly extended from the center of the circular base 11. The shank 12 has a tapered bearing portion 13 that has a diameter gradually reducing in direction away from the circular base 11 (alternatively, the shank 12 can be a tapered member having a diameter gradually reducing from the circular base 11 toward the free end thereof). After installation of the tire stud in the tire 50, the free end of the tapered bearing portion 13 is squeezed to deform by the pin 40 and the wear ring 30, forming a flange 14 that protrudes beyond the surface 51 of the tire 50. Further, the shank 12 has a coarsened surface 15 (see FIG. 6). The coarsened surface 15 is formed by means of a shape design, enhancing the binding strength of the jacket 10 to the tire 50 against torque produced during running of the tire 50, avoiding falling of the tire stud from the tire 50. According to this embodiment, the jacket 10 can be made of ferrite, aluminum, metal alloy containing ferrite, aluminum or copper, or plastics. A ferrite-contained alloy can be carbon steel, alloy steel or stainless steel. Further, the shank 12 is a column, for example, circular column or polygonal column.
The wear ring 30 has a flat top face 32 disposed at the top side thereof, a tapered bottom face 33 disposed at the bottom side thereof opposite to the top face 32 and having a diameter downwardly gradually reducing in direction from the top side toward the bottom side, a bottom edge 34 located on the center of the lowest part of the tapered bottom face 33, and a tapered through hole 31 vertically cut through the center of the top face 30 and the center of the bottom edge 34 and fitting the tapered bearing portion 13 of the jacket 10. By means of the tapered through hole 31, the wear ring 30 is tightly attached to the tapered bearing portion 13 of the jacket 10. After installation of the tire stud in the tire 50, the top face 32 is substantially kept in flush with the surface 51 of the tire 50. According to the present invention, the wear ring 30 is made of ferrite, aluminum, ferrite alloy or aluminum alloy. A ferrite alloy can be carbon steel, forged steel, cast iron or stainless steel. The hardness of the wear ring 30 is higher than the hardness of the jacket 10 (more particularly higher than the hardness of the tapered bearing portion 13 of the jacket 10). Further, the configuration of the wear ring 30 matches the configuration (circular column or polygonal column-like configuration) of the shank 12.
The pin 40 is made of a high hardness alloy, for example, high hardness ferrite alloy or the like, such as tungsten steel, cast iron, alloy steel or stainless steel. The pin 40 is inserted into the inside of the jacket 10 from the top. After installation of the tire stud in the tire 50, the pin 40 partially protrudes beyond the topmost edge of the tapered bearing portion 13 of the jacket 10 and the surface 51 of the tire 50. Because the pin 40 has a hardness higher than the jacket 10, implanting the pin 50 in the jacket 10 from the top (forcing the pin 50 into the jacket 10 with a high pressure) causes the tapered bearing portion 13 of the shank 12 of the jacket 10 to be squeezed outwards, forming a flange 14 that protrudes beyond the surface 51 of the tire 50 and is capped on the top face 32 of the wear ring 30 (the flange 14 is not seen in FIG. 4 because the pin 50 is not yet been driven into the shank 12 of the jacket 10) to prohibit escaping of the wear ring 30 from the jacket 10.
As stated above, the wear ring 30 is sleeved onto the tapered bearing portion 13 of the shank 12 of the jacket 10 substantially kept in flush with the surface 51 of the tire 50. When the tire 50 is being rotated to rub against the road surface, the high hardness characteristic of the wear ring 30 enables the wear ring 30 to resist against high speed and high pressure friction, assuring long service life of the jacket 10. Further, forcing the pin 40 into the relatively softer jacket 10 causes the jacket 10 to be squeezed in between the pin 40 and the wear ring 30, enhancing the tightness among the component parts and avoiding the pin 40 from being forced away by a centrifugal force.
Further, the outwardly protruded flange 14 of the jacket 10 is stopped at the top face 32 of the wear ring 30, working as anti-escape means to prohibit the wear ring 30 from escape.
Thus, when compared to the prior art tire stud design that wears quickly and tends to be forced out of the tire, the tire stud of the present invention has the relatively harder wear ring 30 be attached to the tapered bearing portion 13 of the shank 12 of the jacket 10 to enhance wear resistance during rotation of the tire 50 so that the tire stud does not wear quickly with use. Further, under the protection of the flange 14 of the jacket 10, the wear ring 30 is prohibited from falling away from the jacket 10. Thus, the tire stud of the present invention has wear resistance and falling preventive characteristics.
Referring to FIG. 7, a tire stud in accordance with a second embodiment of the present invention is shown comprising a jacket 10, a locating ring 20, a wear ring 30 and a pin 40. The jacket 10, the wear ring 30 and the pin 40 are same as like component parts of the aforesaid first embodiment. The difference between this second embodiment and the aforesaid first embodiment is that the use of the locating ring 20 in the second embodiment.
The locating ring 20 has a top face 22, a bottom face 23 opposite to the top face 22, a tapered through hole 21 cutting through the top face 22 and the bottom face 23, and a plurality of pawls 24 protruded from the top face 22. The angle of slope of the tapered through hole 21 fits the angle of slope of the tapered bearing portion 13 of the shank 12 of the jacket 10. Further, the transverse width of the top face 22 is greater than the bottom face 23 so that the locating ring 20 defines a tapered peripheral wall 25. By means of the tapered through hole 21, the locating ring 20 is press-fitted onto the tapered bearing portion 13 of the shank 12 of the jacket 10, forcing the bottom edge 211 of the tapered through hole 21 into engagement with the periphery of the tapered bearing portion 13 of the shank 12 of the jacket 10 tightly. The formation of the pawls 24 enhances binding tightness between the locating ring 20 and the tire 50 against torque during rotation of the tire 50 and eliminates or reduces the possibility of falling of the tire stud from the tire 50. Further, the distance between the center of the locating ring 20 and each pawl 24 is greater than or equal to the radius of the wear ring 30 so that the pawls 24 can be forced into the inside 52 (tread design) of the tire 50 to prohibit biasing of the tire stud relative to the tire 50.
Further, the locating ring 20 can be made of ferrite, aluminum, copper or their alloys, or plastics.
According to the aforesaid second embodiment, the extra locating ring 20 enhances the strength of the tire stud against torque from the tire 50, showing superiority of the second embodiment over the first embodiment in eliminating or reducing the possibility of falling of the tire stud from the tire 50.
In conclusion, a tire stud in accordance with the present invention has the wear ring press-fitted onto the shank of the jacket in the tire and kept in flush with the surface of the tread design of the tire to enhance wear resistance against friction during rotation of the tire on a road surface, prolonging the service life of the jacket. Further, the flange of the jacket protrudes beyond the surface of the tread design of the tire and is capped on the top face of the wear ring to prohibit escaping of the wear ring from the jacket. Therefore, the tire stud has wear resistance and falling preventive characteristics, assuring a high level of safety during running of the vehicle on snow.
A prototype of tire stud has been constructed with the features of FIGS. 3∼7. The tire stud functions smoothly to provide all of the features disclosed earlier.
Although particular embodiments of the invention haves been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.

Claims

A tire stud, comprising:
a jacket for embedding in the tread design of a snow tire, said jacket having a circular base and a shank perpendicularly upwardly extended from the center of said circular base, said shank having a bearing portion defined by at least a part thereof;

at least one wearing ring supported on the bearing portion of said jacket, each said wearing ring having a top face disposed at a top side thereof, a tapered bottom face disposed at a bottom side thereof opposite to said top face, a bottom edge located on the center of the lowest part of said tapered bottom face and a through hole vertically cut through the center of said top face and the center of said bottom edge and press-fitted onto the bearing portion of said jacket; and

a pin being axially driven into the bearing portion of said shank and partially protruding beyond the shank of said jacket.
The tire stud as claimed in claim 1, further comprising a locating ring press-fitted onto the bearing portion of said shank of said jacket and disposed at a bottom side relative to said at least one wearing ring, said locating ring having a through hole cut through top and bottom sides thereof and press-fitted onto the bearing portion of said shank of said jacket and at least one pawl protruded from the top side thereof for engaging into the inside of the tread design of a snow tire.
The tire stud as claimed in claim 1, wherein said at least one wear ring has a hardness higher than the hardness of said jacket.
The tire stud as claimed in claim 1, wherein said pin has a hardness higher than the hardness of said jacket.
The tire stud as claimed in claim 1 or 2, wherein the bottom face of said each said wear ring is a tapered face having a diameter gradually reducing in direction from said top face toward said bottom edge of the respective wear ring.
The tire stud as claimed in claim 2, wherein the distance between the center and each pawl of said locating ring is not shorter than the radius of said at least one wear ring.
The tire stud as claimed in claim 1, wherein said shank of said jacket has a coarsened peripheral surface.
The tire stud as claimed in claim 1, 2 or 3, wherein said at least one wear ring is selected from a material group of ferrite, aluminum and their alloys.
The tire stud as claimed in claim 1, 2, 3 or 4, wherein said jacket is selected from a material group of ferrite, aluminum, copper and their alloys, and plastics.
The tire stud as claimed in claim 1 or 4, wherein said pin is made of a metal alloy containing ferrite.
The tire stud as claimed in claim 1, wherein the bearing portion of said shank of said jacket has a flange formed of a top end thereof and stopped at the top face of one said wear ring after the insertion of said pin into said shank.
The tire stud as claimed in claim 1, wherein the through hole of each said wear ring is a tapered through hole having a diameter gradually increasing in direction from the top face toward the bottom edge of the respective wear ring; the bearing portion of said shank of said jacket is tapered bearing portion fitting the tapered through hole of each said wear ring.
The tire stud as claimed in claim 10, wherein said metal alloy is selected from a group of tungsten steel, cast iron, alloy steel and stainless steel.
The tire stud as claimed in claim 1, wherein said locating ring is selected from a material group of ferrite, aluminum, copper and their alloys, and plastics.
The tire stud as claimed in claim 2, wherein the through hole of said locating ring is a tapered through hole having a diameter gradually increasing in direction from the top face toward the bottom edge of the respective wear ring; the bearing portion of said shank of said jacket is a tapered bearing portion fitting the tapered through hole of said locating ring.